Over the years, I've replaced most of the incandescent bulbs in my home and in my studio with LEDs. The incandescents ranged from 35 W low-voltage halogens, to 60 W standard "Edisons", to 75 W reflectors. Meanwhile, the replacement LEDs are 3–12.5 W bulbs. That's a power-requirement reduction of roughly 3,000 W for the 60+ bulbs in my studio building alone. If I were to run those lights for 10 hours/day (like a commercial studio might), I'd be saving 900 kWh of energy per month. At an average cost of $0.16 per kWh for a commercial account in Massachusetts, that would equate to an annual savings of $1,728. Just a few years ago, good LED bulbs cost $20 per bulb. The bulbs I purchased most recently were $7 per bulb. Do the math, and you'll realize that the initial investment in the bulbs will pay off very quickly in energy savings. (LED bulbs last for decades or longer; therefore, you won't be purchasing new bulbs very often.) So, which bulbs should you buy? Other than bulb shape, light output, color temperature, beam width, and wattage — all of which are usually specified in standardized metrics — you should be concerned about audible noise, EMI/RFI, flickering, and dimmability. These last four traits are associated with the driver electronics in the LED bulb, which from my experience, can make or break a bulb (so to speak).
For example, I would not recommend Hyperikon LEDs www.hyperikon.com. I've tried many different styles of Hyperikons that suffer from driver-related problems: RFI emitted by the bulbs cripples nearby wireless equipment, like garage-door openers and producer-talkback remotes; momentary variations in supply voltage cause all of the bulbs on the same circuit to stutter and flicker in unison, horror- movie-like; and in groups of four or more, the bulbs flicker together when used with a dimmer, even an LED-specific one. Moreover, for the 12V MR16 models, the voltage conversion method (magnetic transformer or ELVT, whether LED- compatible or not) doesn't seem to affect the poor performance I've seen from this brand. I also don't recommend the Sunthin LEDs available on Amazon www.amazon.com. These are incredibly cheap (as low as $4 per bulb), but they exhibit visible 60 Hz strobing.